We present experiments that show that gray tracking modifies the parametric gain and the generated wavelengths of a KTP optical parametric oscillator pumped at 532 nm near degeneracy. These perturbations occur over a limited range of pump intensity. We propose a satisfactory model that takes into account photochromic damage, the thermo-optical effect, and the combined processes of creation and saturation of a two-photon absorber at 532 nm. The temperature dependence of Sellmeier equations of KTP is also established at 20–200 °C.
© 2000 Optical Society of America
(160.4760) Materials : Optical properties
(190.4400) Nonlinear optics : Nonlinear optics, materials
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.4870) Nonlinear optics : Photothermal effects
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
Benoît Boulanger, Jean-Philippe Fève, and Yannick Guillien, "Thermo-optical effect and saturation of nonlinear absorption induced by gray tracking in a 532-nm-pumped KTP optical parametric oscillator," Opt. Lett. 25, 484-486 (2000)